Abstract Detail

Systematics

SEO, HEE SEUNG [1], Kim, Seung-Chul [2].

Genetic diversity and differentiation of Ulleung Island endemic flat-leaved stonecrop (Phedimus takesimensis; Crassulaceae).

Ulleung Island is volcanic in origin with ca. 1.8 million years old and is located approximately 137 km east of the Korean Peninsula. Of nearly 500 native species of vascular plants, 39 species (7.8% endemism) are considered to be endemic to Ulleung Island. The origin of endemic species on Ulleung Island is often explained by the mode of anagenetic speciation (88% in Ulleung Island). Therefore, endemic plant species on Ulleung Island represent ideal systems to study anagenetic speciation on oceanic islands. One such example for studying anagenetic mode of speciation on Ulleung Island is Phedimus takesimensis (=Sedum takesimense), which occurs exclusively in Ulleung-do and Dok-do Island. Sedum kamtschaticum (=Phedimus kamtschaticus), which commonly occurs in northeastern Asia, is considered as continental progenitor species of S. takesimense. In this study, we investigated genetic diversity and structure of S. takesimense (derivative) and S. kamtschaticum (progenitor) pairs to assess the genetic consequences of anagenetic speciation. We extensively sampled populations of progenitor (S. kamtschaticum; 11 pops. from Korean peninsula, 88 individuals) and derivative (S. takesimense; 14 pops. 138 individuals from Ulleungdo and 1 pop. 10 individuals from Dok-do) and sequenced five noncoding regions of cpDNA (atpI/H, trnC/ycf6, trnL/F, rps16/trnK, and ndhJ/trnF; ca. 3500 base pairs). We found nearly three times higher haplotype diversity in insular derivative species (21 haplotypes in 93 individuals), which derived from the most common haplotype found in southern and eastern part of Ulleung Island, compared to its continental progenitor species (8 haplotypes in 67 individuals). Only one haplotype found in Dok-do Island was derived from the southwestern population of Ulleung Island. We found no geographical structuring within the island population and very strong genetic differentiation between the island species S. takesimense and its continental progenitor S. kamtschaticum. Given morphological similarity between the species pairs of Sedum, this degree of genetic differentiation is striking and it requires further study based on more extensive sampling of the continental progenitor species. We also found high degree of genetic differentiation among populations of S. takesimense (77% of the variation is found among populations), suggesting substantial population differentiation after speciation. Any factors that contributed to such population differentiation on island are yet to be determined. Nevertheless, our results raise carefully a possibility that anagenetically derived species could accumulate genetic variation through time and high level of genetic differentiation within insular derived species.

1 - Sungkyunkwan University, Department of Biological Sciences, 2066 Seobu-ro, Jangan-Gu, Suwon, Gyeonggi-do, 16419 , South Korea
2 - Sungkyunkwan University, Department of Biological Sciences, 2066, Seobu-ro, Suwon, Gyeonggi, 16419, Republic of Korea

Keywords:
anagenetic speciation
Genetic structure
Crassulaceae
Phedimus takesimensis
Ulleung Island.

Presentation Type: Oral Paper
Session: 14, Systematics I: Basal Dicots, Monocots & Rosids
Location: Sundance 1/Omni Hotel
Date: Monday, June 26th, 2017
Time: 4:00 PM
Number: 14011
Abstract ID:88
Candidate for Awards:None